This invention relates to an innovative locking plate system, and more particularly to such a locking plate system for the locking of bones or vertebral tubercles.
Essential, the prior art locking plate system involves the placement of a plate on two adjacent mobile bone surfaces and then, through a hole defined by the plate, a screw is inserted and used to lock the plate on those bone surfaces. In the prior art, the plate is vulnerable to loosening. Further, the screw is loosened as well, since the contacting surface between plate and bone is not totally matched (due to the different curvatures involved) and the plate is pressed against the bone by the head of the screw. Plates, used to fix the vertebral tubercles, such as: I-plate [See Hansen A, Yuan, MD, et al. Spine, 13(3), 278, 1988]; C.A.S.F. Plate by ArcoMed; A. O. Plate & Screw by Synthes; and Swiss and B. G. Spinal Plate by Howmedica U.K., all use screws to press the plates tightly against vertebral tubercles, but do not combine the screw, the plate and the vertebral tubercles into an integral unit. Therefore, these plates are exposed to the same defect of being easily loosened up as the aforesaid plate systems. In addition, the traditional vertebral tubercles fixation system, such as a Kaneda device, uses a rod and nut to link each vertebral tubercle. When such a system is applied in an operation, the rod is required to shuttle through two screws on the Kaneda plates, resulting in operating difficulties. Furthermore, preplacement of the exterior nut requires the surgical opening to be widened and requires more operating time, leading to more operative hemorrhage. Finally, a Kaneda device is not useable for the ordinary bone fixation.